To achieve this Australia would have to overcome the "awful arithmetic" of serious and sustained carbon emissions cuts that Professor Ross Garnaut described in the climate change review he prepared for the Federal Government.

Over the next 10 years Australians would need to bring their per capita emissions down from about 28 tonnes of carbon dioxide a year to about 16 or 17 tonnes.

The nation would need to reduce its carbon output by the maximum level proposed by the Government, 25 per cent of its 2000 emissions level by 2020, and follow through with a cut of up to 80 per cent by 2050. Other rich nations would have to make similar cuts, and developing countries, including China and India, must slow emissions growth significantly.

Domestically, cutting total emissions by a quarter in the next 10 years would require the nation to attack the problem on several fronts. The Government's target of using 20 per cent renewable power would have to be met or exceeded by 2020.

The forestry industry would have to drastically cut back logging in forests, and major plantations would have to be created as offsets for continuing use of coal-fired power plants.

Most economists and environmental scientists believe this will be difficult but possible.

Research by the Institute of Sustainable Futures in Sydney shows that vast amounts of energy could be saved by better managing peak load power generation. Coupled with wide-scale energy efficiency measures, and some localised, low-emissions power generation, greenhouse gas emissions from the power sector could be slashed.

"You could cut emissions by 10 per cent in 12 months," said the institute's director, Stuart White. "That's the low-hanging fruit – the easy part. The problem is that the price signals to do this aren't there at the moment."

A series of Australian and international studies, including exhaustive modelling by the Federal Treasury, shows that the long-term economic effect of wholesale change on this level will be small. If Australia were to follow the two-degree track to 2050, the effect would be a slowing of economic growth by a few months over four decades.